Solution polymerization schematic flow

ABSTRACT

HYDROCARBON SOLVENT RECOVERED FROM A COMPOSITE OF (A) ELASTOMER DERIVED FROM A LATEX IN WHICH A DITHIOCARBAMATE HAS BEEN USED AS A SHORT-STOPPING AGENT, AND (B) ELASTOMER DERIVED FROM A SOLUTION OF THE ELASTOMER IN SAID SOLVENT, SUCH AS A RUBBER MASTERBATCH WHICH CONTAINS (1) CARBON BLACK, (2) OIL, (3) ELASTOMER DERIVED FROM A LATEX IN WHICH A DITHIOCARBAMATE HAS BEEN USED AS A SHORT-STOPPING AGENT, AND (4) ELASTOMER DERIVED FROM A SOLUTION OF THE ELASTOMER IN SAID SOLVENT, IS TREATED FOR CARBAMATE. THIS IS ACCOMPLISHED IN A CONTAINOUS PROCESS BY FIRST CONVERTING THE CARBON DISULIFIDE TO WATER-SOLUBLE XANTHATE WITH A SOLUTION OF A SODIUM OR POTASSIUM HYDROXIDE REAGENT WHICH IS IMMISCIBLE WITH THE SOLVENT SEPARATES FROM THE SOLVENT AND ON CONTINUED USE BECOMES SATURATED WITH XANTHATE. ANY FURTHER XANTHATE FORMED ISS CARRIED WITH THE SOLVENT AND IS SEPARATED FROM IT BY WASHING WITH WATER, PREFERABLY BY COUNTERCURRENT EXTRACTION. THE REAGENT IS RECUSED IN THE TREATMENT OF FURTHER SOLVENT BY RECIRCULATION, AND ITS CONCENTRATION IS MAINTAINED BY WITHDRAWING SOME OF THE USED REAGENT AND ADDING SOME FRESH REAGENT. THE REAGENT USED IS PREPARED BY DISSOLVING 10 OR PREFERABLY 15 TO 25 PERCENT. AND USUALLY ABOUT 17 PERCENT, OF SUBSTANTIALLY ANHYDROUS SODIUM OR POTASSIUM HYDROXIDE IN 80 TO 95 PERCENT METHANOL. DURING THE TREATMENT OF THE SOLVENT, WATER IS FORMED, AND AFTER THE OPERATION HAS BEEN FUNCTIONING FOR SEVERAL HOURS THE REAGENT USED CONTAINS ABOUT 15 TO 30 PERCENT OF WATER. THE SOLVENT IS USUALLY HEXANE OR OTHER ALIPHATIC SOLVENT SUCH AS BENOR 8 CARBON ATMOS, BUT AN ORGANIC SOLVENT SUCH AS BENZENE OR TOLUENE MAY BE EMPLOYED.

DEFENSE/E PULlEATlON UNITED STATES PATENT OFFICE Published at the request of the applicant or owner in accordance with the Notice of Dec. 16, 1969, 869 O.G. 687. The abstracts of Defensive Publication applications are identified by distinctly numbered series and are arranged chronologically. The heading of each abstract indicates the number of pages of specification, including claims and sheets of drawings contained in the application as originally filed. The files of these applications are available to the public for inspection and reproduction may be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to the merits of alleged invention. The Patent Otfice makes no assertion as to the novelty of the disclosed subject matter.

PUBLISHED DECEMBER 14:, 197 l "ran m EH SAMPLE EXTRACTION column adiiw iin Hydrocarbon solvent recovered from a composite of (a) elastomer derived from a latex in which a dithiocarbamate has been used as a short-stopping agent, and

(b) elastomcr derived from a solution of the elastomcr in said solvent, such as a rubber masterbatch which contains (1) carbon black, (2) oil, (3) elastomer derived from a latex in which a dithiocarbamate has been used as a short-stopping agent, and (4) elastomer derived from a solution of the elastomer in said solvent, is treated for removal of carbon disulfide generated from the dithiocarbamate. This is accomplished in a continuous process by first converting the carbon disulfide to water-soluble Xanthate with a solution of a sodium or potassium hydroxide and methanol, and subsequently separating the xanthate from the solvent. The unreacted methanol-hydroxide reagent which is immiscible with the solvent separates from the solvent and on continued use becomes saturated with xanthate. Any further xanthate formed is carried with the solvent and is separated from. it by washing with water, preferably by countcrcurrent extraction. The reagent is reused in the treatment of further solvent by recirculation, and its concentration is maintained by withdrawing some of the used reagent and adding some fresh reagent.

The reagent used is prepared by dissolving or preferably to percent, and usually about 17 percent, of substantially anhydrous sodium or potassim hydroxide in to percent methanol. During the treatment of the solvent, water is formed, and after the operation has been functioning for several hours the reagent used contains about 15 to 30 percent of water. The solvent is usually hexane or other aliphatic hydrocarbon of 4 to 7 or 8 carbon atoms, but an organic solvent such as benzcne or toluene may be employed.

H. MOOSAVIAN T893 OO5 PROCESS FOR REMOVING CARBON DISULFIDE FROM AN ORGANIC SOLVENT BY EMULSIFlOATION EMPLOYING AN ALCOHOLIC ALKALI HYDROXIDE LATEX POLYMER CEMENT OIL CARBON BLACK SOLVENT Original Filed July 18, 1967 COAGULATION TANK 2 Sheets-Sheet 1 1 POLYMER mums (SOLVENT FREE) FIG! STEAM BLACK MASTERBATCH SCHEMATIC FLOW DIAGRAM CATALYST MONOMER PUREFICATION COLUMN SOLVENT MIXED FEED [REACTOR STORAGE A2 STEREORUBBER M CEMENT FIG. 3

SOLUTION POLYMEIREZATION SCHEMATIC FLOW DIAGRAM D EQ 14, 171 MOQSAVIAN 1 893 905 PROCESS FOR hEMOVlNG CARBON DISULFIDE FROM AN OHUANlU SOLVENT BY EMULSIFlCATION EMPLOYING AN ALCOHOLIC ALKALL HYDROXLDE Original Filed July 18, 1967 u Sl10cLsShe0t 2 

